Coil grab



Oct 20, -1964 l.. G. KAPLAN ETAL 3,153,555

COIL GRAB 5 Sheets-Sheet 2 Filed March 6. 1961 INVENTORS: LOUIS G.KAPLAN WILLIAM S. BENES CHEN-NU YU NOE ATT'Y COIL GRAB 5 Sheets-Sheet 3Filed March 6, 1961 INVENTORS: LOUIS G. KAPLAN WILLIAM S. BENES CHEN- OYU Oct. 20, 1964 L. G. KAPLAN ETAL COIL GRAB hwm 4 t wm MAN W o o NmE hE B S A WKs S. l. .m wm G M h hm .wm SM S OO wl- 5 5w; 0"

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ATT'Y Oct. 20, 1964 L. G. KAPLAN ETAL COIL GRAB 5 Sheets-Sheet 5 FiledMarch 6. 1961 INVENTORSZ LOUIS G. KAPLAN WILLIAM S. BENES CHEN-NUC U BYM4,

ATT'Y nited States Patent Iliinois Filed Mar. 6, 196i, Ser. No. 93,390Claims. (Cl. 294-88) The present invention relates to motorizedindustrial coil lifters of the type commonly known as coil grabsinasmuch as they include cooperating jaws which engage the cylindricalcoil Wall therebetween and exert inward pressure upon the same totightly compress the convolutions of the coil and obtain a sufficientgrip upon the coil wall as to enable the coil to become elevated fromthe supporting surface when the lifter as a whole is bodily raised. Coilgrabs of this general character are commonly employed at the steel millfor handling relatively heavy and massive coils of sheet metal stockwhich are wound in involute fashion to produce the cylindrical coils. Acoil grab of this type is to be distinguished from a lifter whichemploys cooperating tongs having either tong foot members adapted toslide beneath a coil when the latter is disposed in a vertical positionon a pallet, or tong fingers adapted to enter the central bore of ahorizontally disposed coil when the latter is disposed in a horizontalposition on the floor or other supporting surface.

Present day motorized coil lifters are of two general types, namely, thetong type wherein the coil-gripping jaws are carried at the lower endsof a pair of motor driven tong arms which, by virtue of a limitedmechanical advantage otfered by the tong leverage action, exert agripping force on the coil walls to assist in lifting, and thehorizontally extensible jaw type wherein a motor driven movable jaw iscapable of being driven toward and away from a fixed jaw on the coillifter frame.

The limited gripping force which can be attained with either of thesetypes of lifters renders them incapable of lifting objects such as Coilsby friction alone and thus such lifters are invariably provided withfoot members which are adapted to pass beneath the object to be liftedso as to carry the major portion of the load.

Where lifting must be accomplished solely by means of a friction grip, agrab-type mechanism is employed which operates upon the principle of aconventional ice tong, one example of such a grab vbeing shown anddescribed in United States patent to Zito, No. 2,803,489, dated August20, 1957, and entitled Load Lifting Device of the Self-Gripping Type.

Such tong type grabs `are possessed of several limitations that leavemuch to be desired from the standpoint of efficiency. In the firstplace7 in order to accommodate the lifting of coils having coil Walls ofvarying thicknesses, the extent of jaw spread must be appreciable. This,of necessity, requires the use of tong arms which are relatively longand thus have a wide sweep. Movement of, the tong arms from open-jawtoclosed-jaw position and vice versa requires a very appreciable headroom uniess an additional manual jaw opening adjustment is imposed intothe mechanism. Where such grabs are concerned, the adjustment requiresthe use of ladditional operating personnel on the lioor and it alsonecessitates an interruption in the use of the machine during theeffecting of the adjustment.

An equally serious limitation that is attendant upon l the use of tongtype coil grabs resides in the fact that in order to move the grab awayfrom a previously deposited coil, it is lnecessary to open the grabjaws-to the full' est extent of which they are capable before the jawice an appreciable amount of idle hoist operation for moving the tongarms between their extreme open-jaw and closedjaw positions each time acoil is handled. This, in light of the large vertical hoist displacementinvolved in driving the jaws, is a time-consuming operation. A thirdlimitation that is attendant upon the use of tong type coil grabsresides in the fact that because the empty coil grab must be locked in acollapsed condition while travelling between successive coils to belifted, such locking precludes the operator from performing thetime-saving expedient of operating the jaws to condition the grab forengagement with the next succeeding coil to be lifted during the traveltime of the empty grab between coils.

The present. invention is designed to overcome the above-notedlimitations that are attendant upon the construction and use ofconventional coil grabs and, toward this end, it contemplates theprovision of a coil grab which embodies certain of the advantageousfeatures of a tong type coil grab and certain other advantageousfeatures of a horizontally movable jaw coil lifter to produce a grabwhich possesses the high gripping power ordinarily associated with atong type grab but which does not require an inordinate amount of headroom or wide aisle space between adjacent coil rows; which will releasea given coil as soon as the gripping pressure on the coil wall isrelieved so that it is not necessary to move the jaws to their extremeopen position before the empty grab may be lifted away from a coil, orto move the jaws between their extreme positions each time a coil isengaged, lifted, transported and deposited at a remote location; whichwill enable the operator to make jaw adjustments while the empty grab isin transit between coils so that the grab may be caused to arrive in thevicinity of a given coil to be lifted with the jaws in an approximatelycorrect condition `for operative coil engagement; and which need make nocompromise between jaw travel speed and power train gear rerductioninasmuch as coil gripping force is not dependent upon motor outputtorque.

Y The provision of a coil grab of the type briefly outlined above beingamong the principal objects of the invention, it is a further andimportant object to provide a grab having associated therewith a fixedjaw and a movable jaw, the latter being slidably carried at the lowerend of atong arm so as to be movable toward and away from the fixed jawin the usual manner of tong operation when the upper end of the tong armis moved in one vdirection or the other, together with auxiliary andindependently operable motor driven means for shifting the movable jawtoward and away from the fixed jaw without affecting the position of thetong arm or its fulcrum point. By such an arrangement, the power whichis employed for shifting the movable jaw in this manner may be appileddirectly to the coil wall by closure of Y the jaws against the Isame to.compress the coil laminacontrol mechanism by means of which theoperator is obliged to position the coil grab as a whole relatively to acoil to 'be lifted in such a manner that when the jaws `are closed uponthe coil wall they will fuliy engage the wall coextensively with thejaws so that all operaf tive gripping points on the jaws will obtain thebenefit of frictional resistence to jaw slippage.

o as

A similar and related object of the invention is to provide such a coilgrab whereby such initial positioning of the grab mechanism relativelyto the coil is a prerequisite to the attainment of sufficient tongaction to effect coil elevation. By such an arrangement, in the eventthat the operator attempts to elevate the coil without so initiallypositioning the coil grab for full coil engagement, coil slippage willtake place immediately instead of after the coil has been elevated.

Yet another object of the invention is to provide a coil grab havingassociated therewith novel latch mechanism which is automaticallyoperable when the operator lifts the empty grab without load to disablethe tong action of the grab, and which is also automatically operablewhen the operator lifts the coil-loaded grab to render the tong actioneffective.

A still further object of the invention is to provide a coil grab ofthis sort which reduces the amount of jaw movement incident to eachcomplete coil-transporting to a minimum.

The above mentioned objects are related to principal features of noveltyassociated with the present invention but numerous other ancillaryobjects and advantages of the invention not at this time enumerated willbecome readily apparent as the nature of the invention is betterunderstood.

In the accompanying ve sheets of drawings forming a part of thisspecication, two exemplary embodiments of the invention have been shown.

In these drawings:

FIG. 1 is a side elevational view, partly in section, of a coil grabconstructed in accordance with the principles of the present inventionand showing the same in a suspended load-free position;

FIG. 2 is an end elevational View of the structure shown in FIG. 1 withcertain parts removed in the interest of clarity;

FIG. 3 is a fragmentary side elevational view of the structure shown inFIG. 1 showing the coil grab in an initial coil-engaging positionpreparatory to closure of the coil-engaging jaws upon a coil;

FlG. 4 is a side elevational view similar to FIG. 3 showing the coilgrab in an elevated coil-supporting position;

FIG. 5 is a circuit diagram, schematic in its representation, of theelectrical instrumentalities associated with the coil grab of FIG. 1;

FIG. 6 is a side elevational view, partly in section and similar to FIG.l, showing a modied form of coil grab constructed according to thepresent invention;

FIG. 6a is an enlarged plan view of a latch member employed inconnection with the present invention;

FIG. 7 is a fragmentary side elevational view similarl to FIG. 3 showingthe coil grab of FIG. 6 in an initial coil-engaging position;

FIG. 8 is a side elevational View similar to FIG. 4 showing the coilgrab of FIG. 6 in an elevated coil-supporting position; and

FIG. 9 is a schematic circuit diagram of the electricalinstrumentalities associated with the coil grab of FIG. 6.

Referring now to the drawings in detail and in particular to FIGS. l to4 inclusive, in these views one exemplary form of coil grab constructedin accordance with the principles of the present invention has beenillustrated in several diiferent positions. In FIG. l the empty grab,which has been designated in its entirety at 16, is shown as beingpositioned above a coil C to be lifted preparatory to be lowered intocoilengaging position. In FIG. 3 the grab lil is shown as being seatedupon the upper annular face of the coilV C preparatory to closing of thegrab jaws upon the coil. ln FIG. 4 the grab is shown as beingoperatively applied to the coil C in lifting relationship and with thegrab under the full load of the coil which is' suspended thereby.

The grab l@ involves in its general organization a xed jaw 1 2 and amovable jaw 14, the latter being movable in opposite directionshorizontally toward and away from the xed jaw for coil clampingpurposes. When in operative lifting relationship with respect to thecoil C as shown in FIG. 4, the xed jaw 12 projects into the central bore16 of the coil, while the movable jaw 14 engages the cylindrical outersurface 18 of the coil. The various involute coil laminations 19 arethus squeezed or compressed between the two jaws 12 and 14 withsutl'icient pressure being exerted upon the coil to permit lifting ofthe latter without danger of slippage.

The jaw 12 is iixedly secured to the underneath portion of the grabframework Ztl and it depends below the level of a flat thrust plate 22which constitutes a portion of the framework 2t). The thrust plate 22 isadapted to seat upon the upper end 24 of the coil C as shown in FIG. 3at the time that the grab is initially brought into lifting relationshipwith respect to the coil while the latter is supported upon the iloor 26or other supporting surface from which the coil is to be elevated, allin a manner and for a purpose that will be made clear presently. Theframework Ztl further includes side plates 28 and 3@ respectively (FlG.2), a top plate 32, a rear plate 34, a vertical partition wall 36, and apair of transversely extending supporting shelves 38 and 40 for anelectric motor M and a gear reduction device 42 respectively.

The fixed jaw 12 includes a relatively heavy jaw body 44, a pair oftriangular reinforcing webs or gussets 46 and an inclined plate 48 whichbridges the two webs 46. The front face Sil of the jaw body 44 is ofconvex cylindrical configuration to accommodate the curvature of thecylindrical bore 16 of the coil C.

The movable jaw 14 includes a jaw body 52 having a front face 54 ofconcave cylindrical conguration to accommodate the curvature of theoutside cylindrical surface 18 of the coil C, and a plurality ofrearwardly extending ears S8 by means of which the jaw as a whole ispivoted on a jaw carriage 60. The jaw carriage 60 is comprised of a pairof spaced parallel vertically disposed plates 62 (FIG. 2) which carryadjacent their upper longitudinal edges respective shoes 63 which areconfined between upper and lower iixed hardened steel guide rails 64 and66 respectively mounted on the side plates 28 and 30. The forward orouter ends of the plates 62 project downwardly below the level of theflat thrust plate 22 and a pivot pin 68 extends between the plates andprojects through the ear 5S, thus pivotally mounting the jaw body 52 onthe carriage 6l? for limited rocking movement thereon. The lower edge ofthe curved jaw body 52 is flared downwardly and outwardly at lli toassist in guiding the jaw into operative relationship with the coil Cduring. initial coil and grab alignment. From the above description itwill be seen that the movable jaw assembly, including the jaw 14 and itssupporting carriage 60, is capable of horizontal sliding movement in afore and aft direction so that the jaw body S2 may be moved toward andaway from the ixed jaw body 44 for coil-engaging and coil-releasingpurposes respectively. The pivotal connection between the jaw 14 and itssupporting carriage 66 enables the jaw to align itself with the outersurface 13 of the coil.

A relatively heavy feed screw 72 having a threaded portion '73 and anon-threaded portion 74 extends longitudinally of the framework 2d andis rotatably and slidably journalled at its ends in front and rearbearing assemblies 75 and 76. The threaded portion of the screw 7 2receives thereon a nut 73 adapted to travel longitudinally along thescrew. The nut 78 is xedly secured to the carriage @il and moves bodilytherewith so that upon rotation of the screw 72 the carriage will be fedin one direction or the other longitudinally of the grab.

The non-threaded portion '74 of the feed screw 72 projects through andis rotatable in a cylindrical boreSt) provided in a slide block 82having trunnions 84. The trunnions project into vertical slots 86provided in the lower if d ends .of a pair of spaced parallel sidemembers 8S which considered collectively constitute an elongated tong orlever arm 90. The upper end of the tong arm 9i) carries a load-carryingcross pin 92 which is pivoted to the lower end of a lifting bail 94. Theupper end of the bail 94 carries a hook-engaging pin 96 designed forcooperation with the lifting hook 9S of an overhead crane or othersuitable hoisting mechanism. The lower medial region of the tong arm 90is pivotally connected to the grab framework 20 by means `of a pivot pin99 which extends transversely between the side plates 28 and 30 andwhich passes through the two side members 8S as best seen in FIG. 2.

The feed screw '72 is capable of limited longitudinal axial slidingmovement in the bearings '75 and 76 for a purpose that will become clearpresently. The slide block 82 is adapted to bear at its rear sideagainst a thrust shoulder 100 and an appreciable clearance existsbetween the lfront face of the block and the front bearing 7 S thusdetermining the extent to which the feed screw 72 may shiftlongitudinally of the grab framework 20.

As best seen in FIG. 1, the feed screw 72 is adapted to be selectivelyrotated in either direction through a power train leading from anelectric motor M suitably mounted on the supporting shelf 3S. The powertrain extends from 'the motor .shaft 102 through va conventional torquelimiting device 104 and the gear reduction device 42 and it includes agear train having an input gear 1138 mounted on the output shaft 11) ofthe gear reduction device, an idler gear 112 and a relatively wideoutput gear 114 mounted directly on `the feed screw 72 and keyed to thelatter. The width of the gear 114 is such as to accommodate the fullextent of longitudinal shifting movement of the feed screw whilemaintaining full mesh between `the gear 114 and the idler gear 112.

A supporting link 121i projects upwardly from the rnedial regions of thegrab framework 20 and has its lower region welded or otherwise securedthereto. The upper end `of the link 12d Ais formed with a hook portion122 designed for cooperation with a secondary lift pin 124 which extendsbetween the side members 83 of the tong `arm 91D near the upper end ofthe latter and immediately below the cross pin 92. A pressure bar 126extends across the lifting bail 94 and is adapted to be engaged by theunderneath side of the lifting hook 9? under certain circumstances whenthe operator of the overhead crane is in the process of engaging a coiland as will be set forth presently.

As shown in FIG. 1, the previously mentioned vertical partition Wall 36,in combination with the end wall 34, establishes a compartment or spaceadapted to contain a ballast or counterweight 128 in order to compensatefor any unbalanced forces which may exist when the grab assembly issuspended from the lifting hook 98.

Still referring to FIG. 1, upper and lower limit switches 136 and 132respectively are suitably mounted on the grab framework 21B and aredesigned for selective cooperation with an actuating finger 134 carriedon the tong arm 90. As shown in the circuit diagram of FIG. 5, the twolimit switches 130 and 132 are connected in electrical parallel in thecircuit for the electric motor M so `that upon engagement of eitherlimit switch by the actuating finger 134, the normally open motorcircuit will become closed. Speciiically, and as shown in the circuitdiagram of the limit switch 131i, a circuit will exist from one side ofthe power line S through leads 14d, 142, contacts of the switch 139,leads 144, 146, reversing switch SR, motor M, and lead 14S to the otherside of the line. Upon closure of the limit switch 132 `a similarcircuit will exist from the power line S through leads 141B, 150,contacts of the switch 132, leads 152, 146, reversing switch SR, motor Mand lead 138 back t-o the line. The reversing switch SR Iis adapted tobe lpositioned at a remote location, for example, in the operators cabof the overhead crane or hoist.

In the operation of the apparatus, when the empty grab is suspended fromthe crane lifting hook 9S with the pin 124 supporting the hook portion122 lof the supporting link 120, and consequently supporting the entireweight of the grab 10 as shown in FIG. l, the tong arm 9i) is biased in`a counterclockwise direct-ion so that the slide block 82 is heldagainst the thrust bearing and the feed screw 72 is retained rearwardly,i.e. to the right but no load is limposed upon the feed screw. Theactuating linger 134 `on the ltong arm 9i) remains in engagement withthe upper limit .switch so that the motor circuit is capable of beingclosed by the operator who may actuate the reversing switch SR at willto cause operation of the motor in one direction or the other asdesired. The operator will normally cause the feed screw 72 to beactuated in a direction to move `the nut 78 to the left as viewed inFIG. l and shift the jaw carriage 60 to Ia position wherein the movablejaw 14 is removed from the fixed jaw 12 a distance. sufficient toaccommodate reception of the wall of the coil C to be lifted between thesame. The operator will then lower the grab 10 over the coil, with thetwo jaws 12 and 14 straddling the wall of the coil, until such time asthe thrust plate 22 seats squarely upon the upper end face 24 of thecoil as shown in FIG. 3.

Continued lowering of the lifting hook 98 will place the entire weightof the grab 10 upon the coil and subsequently the pin 124 will movedownwardly and be released from the hook portion 122 of the hookedsupporting link 120, .thus relieving the tension on this link. Thedownward movement of the pin 124 relatively to the hook portion 122 maybe augmented by the weight `of the lifting hook 98 and its supportingstructure bearing against the pressure Ibar 126 carried by the bail 94which in turn acting through lift pin 92 force-s the upper end of thetong arm 9d downwardly. This downward movement of the upper end of thetong arm 9@ causes the arm to pivot about the taxis of the pin 99 in aclockwise direction as viewed in FlG. 3 so that the slide block 82 movesto the left and engages the `fro-nt feed screw bearing 75.

As soon as the tong arm 9i) commences its clockwise Aswinging movement,as set forth above, the actuating finger 134 moves out of operativeengagement with the limit switch 130, thus disabling the motor circuitso that the operator may not close the movable jaw 14 `against thelfixed jaw 112 to grip the coil therebetween. As soon as the actuatinglinger 134 engages the lower limit switch A13,2, the .motor circuitagain becomes potentially closed and the operator may then actuate thereversing switch SR of the motor M to rotate the feed screw 72 in adirection to cause the movable jaw 14 to move horizontally toward thefixed jaw 12 so that the two jaws will engage the wall Zof the coil andcompress the same therebetween, thus forcing the screw 72 in thedirection of the front bearing 75 and until the thrust shoulder 100engages the slide block 82. At such time as the wall of the coil hasbeen engaged and squeezed by the two jaws 12 and 14, continued rotationof the motor shaft 162 will effect slipping of the torque limitingdevice 1114 with no further rotation of the feed screw taking place. Atthis time, however, sufficient pressure is exerted upon the wail of thecoil to compress the various coil laminations 19 against one another andtake up Vmost of the slack which may exist in the coil due to theloosely wound laminations thereof.

With the grab in the condition just outlined, the operator will thenactuate the crane to cause the lifting hook 93 to become elevated so asto engage the pin 96 and lift the bail 94. At this time, a powerful tongleverage action will obtain and the lower end of the tong arm @itil willoperate through the trunnions 84 to force the slide block 82 to theright `as viewed in FIG. l. Such movement of the slide block will shiftthe feed screw '72 and nut 73 to the right and cause the entirejaw-supporting carriage d@ and movable jaw 14 carried thereby to exert,in combination with the fixed jaw 12, a powerful gripping action on thecoil for lifting purposes. Continued upward movement of the lifting hook9S and bail 94 will cause the thus gripped coil to be elevated from thesupporting surface as shown in FlG. 4 for transportation to a remotelocation.

It is to be noted at this point that since the upper limit switch 130 isengaged by the actuating finger 134- when the weight of the grab isborne by the hooked link 12b, the contacts of this limit switch remainclosed so that the operator may energize the motor circuit for actuationof the movable jaw 14 in either direction of movement. He is thus unableto close the jaws 12 and 14 prematurely upon the coil C before thethrust plate 22 has become seated upon the upper end face 24 of thecoil. In such an instance, inasmuch as the pin 124 will not have movedaway from the hooked end 122 of the link 120, the slide block S2 willremain in contact with the thrust bearing 10@ and the feed screw 72 willhave no freedom of movement under the influence of the upward thrustexerted upon the tong arm 90 by the lifting bail 94. ln other words, thetong arm will not be freed for independent counterclockwise swingingmovement due to the engagement between the supporting link 129 `and thepin 124. Therefore the only pressure that will be applied forcoilgripping purposes is that which is supplied by the motor M throughrotation of the feed screw 72 and the design of the apparatus is suchthat this pressure is insufficient to compress the coil laminations 19to such an extent that the coil may be lifted. Any attempt on the partof the operator of the overhead crane to raise the lifting hook 98 forcoil lifting purposes at this time will result in the jaws 12 and 14slipping from the coil wall and without elevation of the coil from thesupporting surface.

The hooked portion 122 of the supporting link 120 and the cooperatingpin 124 constitute in effect a pin and slot type lost-motion connectionwhich must be made effective before sufficient gripping pressure can beimposed upon the coil to lift the same from the supporting surface.Unless the thrust plate 22 be caused to seat upon the upper end face 24of the coil, the supporting link 129 cannot be freed from the pin124iand the lostmotion necessary to tightly compress the coillaminations preparatory to coil-lifting operations cannot be attained bythe tong arm, because the tong arm 9d itself is not freed for swingingmovement in a counterclockwise direction. If the tong arm is not thusfreed, the pin 124 serves as a secondary lift pin and bears the entireweight f the grab. Stated otherwise, the hook portion 124iconstitutes alimit stop abutment for the upper end of the tong arm 90 to limit theextent of counterclockwise swinging movement of the tong arm when thegrab is empty.

Mere touching or seating of the thrust plate 22 upon the upper end face24 of the coil C and a consequent relief of lifting pressure upon thepin 124 is not sufficient to effect adequate jaw pressure upon the coilC to permit lifting of the coil. The pin 124 must move downwardly awayfrom the hook portion 122 of the supporting link 2'!) a suiicientdistance to establish the necessary lost motion clearance between theslide block 82 and the thrust bearing 1d@ at the time the wall isinitially engaged by the jaw 14 so that the feed screw '72 may beshifted fully to the left for subsequent slack take-up and coilcompressing operations when the leverage olfered by the tong arm 9&9 isexerted upon the feed screw due to lifting of the upper end of the tongarm as previously described.

Referring now to FIG. 5, it will `be noted that the finger 134 has anappreciable path of travel between the two limit switches 13b and 132. Aslight initial clockwise movement of the tong arm 9@ will cause thefinger 134 to immediately disengage the limit switch 13@ and open themotor circuit so that the gripping jaws are inoperative and cannot bemoved. These jaws will remain inoperative until such time as the linger134 has travelled the full distance between the two limit switches andhas engaged the limit switch 132, thus again establishing the motorcircuit so that the jaws may be operated. By such an arrangement, themotor circuit may be energized only when the pin 124 is in liftingengagement with the hook portion 122 during hoisting of the empty grab,or when the thrust plate 22 is seated on the upper end of the coil andthe lifting action of the crane hook 9S is inelfective so that the tongarm @il moves to an extreme clockwise position. Stated otherwise, thegripping jaws of the grab may not be motor-actuated in an intermediateposition of the tong arm.

By virtue of the phenomena described above, upon initially elevating thecrane hook 98 after the thrust plate 22 has been seated on the coil C,the gripping pressure imposed upon the coil will result in a slightcounterclockwise movement of the tong arm which will be suiiicient tomove the actuating nger 134 out of contact with the limit switch 132 tointerrupt the motor circuit. Thus, when the coil is suspended duringtransportation thereof from one place to another, the operator may notinadvertently open the motor circuit and drop the coil.

After the coil C has been lifted in the manner previously described andthe crane lifting hook 98 lowered so as to lower the grab as a whole anddeposit the coil C on the supporting surface 26 at a remote location,the tong arm Si@ will move in a clockwise direction so that theactuating linger 134i will again shift to the limit witch 132, thusclosing the contacts of the latter switch and enabling the operator toactuate the motor M in a direction to cause jaw opening movements forcoil-releasing purposes.

In FiGS. 6 to 9 inclusive, a modiiied form of coil grab 311i has beenillustrated, In this form of the invention, the grab framework 324i, thefixed and movable jaws 312 and 314, respectively, the tong arm 39d, themotor M2 (FIG. 9), and the power train including the gear reductiondevice and gear train leading therefrom remain substantially the same orsimilar to the corresponding parts in the form of the inventionpreviously described so that needless repetition of description may beavoided by the application of corresponding reference numerals but of ahigher order to the corresponding parts as between FlGS. l to 4inclusive and FIGS. 6 to 9 inclusive.

In this latter form of the invention the hooked supporting link 12b ofFlG. l, its cooperating pin 124i, the two limit switches 131B and 132and the actuating tinger 134 have been dispensed with and in their steadthere have been substituted a different form of latch mechanism andsafety control circuit.

As best seen in FGS. 6, 6ft and 8 a spring biased oating latch member3211 is pivoted as at 313 adjacent to the upper end of the tong arm 390and is provided with a latch seat 315 and an overlying latch guideshoulder Sli. A spring 367 has one end attached as at 369 to the tongarm 32?@ and has its other end attached as at 321 to the latch member311 and serves to bias the floating latch member to a mid-position ofequilibrium.

The floating latch member 311 is designed for cooperation with a latchpin 323 provided on a hook plate 325 which is pivotally supported from asuspension pin 327. The lower end of the hook plate 325 is provided witha hook portion 329 designed for cooperation with a pin 331 carried atthe upper end of a supporting ear 333.

A limit switch 335 having normally open contacts is adapted to beengaged by an actuating arm or lever 337 pivoted as at 339 on a bracket341 carried on the top plate 332 of the grab framework 32d, The rear endof the actuating lever 337 is normally urged upwardly by means of acompression spring 343 mounted on a guide post 345 so that the normallyopen contacts of the limit switch 335 are yieldingly urged to theirclosed position. The hook plate 325 carries an actuation pin 347 whichis designed for engagement with the lever 337 but which, when the hookplate 32S and pin 331 are in operative engagement, is normallymaintained out of contact with the lever 337. As will be described ingreater detail when the operation of the grab is set forth, when thehook plate 325 moves downwardly relatively to the pin 331 and leaves thesame, the lower end of the hook plate is caused to swing to the right asviewed in FG. 6 due to a camming action which takes place between thepin 331 and an inclined cam surface 349 on the inside of the hookportion 329. In thus swinging to the right, the pin 347 engages thelever 337, as shown in dotted lines in FIG. 9, and causes the same torock in a clockwise direction against the action of the compressionspring 343, thus releasing the limit switch 335 and allowing thenormally open contacts thereof to move to their normal position and openthe motor circuit. Continued swinging movement of the hook plate 325will finally cause the pin 347 to move away from the lever 337, as shownin FIG. 9 in broken lines, so that the lever will again engage the limitswitch 335 and close the normally open contacts thereof to restore themotor circuit.

The limit switch 335 is disposed in the motor circuit, as shown in FIG.9, so that upon closure of the contacts associated therewith a circuitwill extend from the power line S through lead 351, limit switch 335,lead 353, reversing switch SZRZ, motor M2 and lead 355 back to the lineS.

In the operation of the apparatus shown in FIGS. 6 to 9 inclusive, whenthe empty grab 310 is suspended from the crane lifting hook 93, as shownin FIG. l, and with the hook portion 329 of the hook plate 325supporting the pin 331, and consequently the entire weight of the grab310, the tong arm 390 is biased in a counterclockwise direction so thatthe slide block 382 is forced against the thrust shoulder 390 and thefeed screw 372 is rearwardly, i.e. to the right, as shown in FIG. 6, butno load is imposed upon the feed screw. The actuating pin 347 remainsout of engagement with the lever 337 so that the contacts of the limitswitch 335 are closed and the motor circuit is under the control of thecrane operator who may actuate the reversing switch S2RZ at will todrive the motor in either direction as desired.

After causing the feed screw 372 to shift the jaw carriage 36@ to theleft, as viewed in FG. 6, thus to open the jaws to such an extent thatthey may straddle the coil wall, the grab 310 may then be lowered overthe coil so that the jaws will straddle the coil wall and the thrustplate 322 will seat squarely upon the upper end face 24 of the coil.Thereafter, continued lowering of the hook 93 will place the entireweight of the grab 31u upon the coil and as a consequence the hook plate325 will move downwardly and release the pin 331 while at the same timeit will make camming engagement with the surface 349 so that it willswing to the right as viewed in FIG. 6. The pin 323 will Contact theunderneath surface 351 of the latch seat 315, thus causing the latch31]. to rotate bodily in a counterclockwise direction about the axis ofthe pin 313 until such time as the pin 323 clears the upper end 353 ofthe seat 315 and moves against the side 365 of the latch shoulder 317.At the same time, the tong arm 396) will move in a clockwise directionwhile the slide block 332 will move to the left and engage the frontfeed screw bearing.

As soon as the hook plate 325 commences its downward movement asdescribed above the pin 347 engages the lever 337 and moves the sameagainst the action of the spring 343, thus causing the left hand end ofthe lever to release the limit switch 335 and allow the normally opencontacts associated therewith to become open to prevent energizing ofthe motor circuit. The circuit will remain open until such time as thehook plate 325 has been swung fully to the right and the slide block 332has engaged the front thrust bearing 375. At this time the hook platewill assume the broken line position wherein it is shown in FIG. 9 andthe pin 347 will release the lever 337 and effect closing of thecontacts of the limit switch 335.

The operator of the crane may at this time energize the motor circuitand cause operation of the motor M2 so as to effect rotation of the feedscrew 372 irl a direction to close the jaws 312 and 314 on the wall ofthe coil in the manner previously described. As such time as suiicientpressure is exerted upon the wall of the coil to tightly compress thelaminations thereof, the torque limiting device 404 will slip and nofurther rotation of the feed screw will take place. The operator may nowelevate the crane lifting hook 98 so as to engage the lift pin 396 andlift the bail 394 and thus exert an upward pull upon the tong arm 399and effect a powerful gripping action upon the coil for lifting purposesin the manner previously described in connection with the form of theinvention shown in FIGS. l to 5 inclusive. As the crane hook 98 israised to lift the coil from the supporting surface, the latch seat 315will maintain the hooi; plate in the out-of-way position described aboveand as shown in FIG. 8. Continued raising of the coil grab 314B willplace the entire weight of the grab and coil upon the tong arm 390 andeffect the powerful gripping action of the jaws 312 and 314 on the coilwall as previously described in connection with the form of theinvention shown in FIGS. l to 4 inclusive.

After the coil C has been transported to the remote location and thecrane hook 98 and bail 394 lowered to deposit the coil on the supportingsurface, continued downward movement of the grab will cause the pressureplate 322 to seat upon the upper end surface 24 of the coil so that thetension on the tong arm 390 will be relieved. As the hook 98 and bail394 continue their downward movement, the pressure of the hook upon theplate 426 will lower the upper end of the tong arm so that the pin 323will ride upwardly on the surface 369 and onto the surface 371 of thelatch shoulder 317 where it will remain until such time as the coil hasbeen released and the empty coil grab again elevated.

At this point, the operator will actuate the motor M in a direction tomove the jaw 314 away from the jaw 312 a distance just suliicient torelease the coil wall, after which he will elevate the crane hook 98 andpull the upper end of the tong arm 33u upwardly. The pin 323 will thenride downwardly relative to the latch seat 315 and slide on the outsidesurface 373 thereof until it clears the bottom end 375 of the seat,whereupon the spring 367 will restore the latch member 311 to its normalfloating position of equilibrium and the parts will? be restored to theposition in which they assume in FIG. 6.

T he two forms of the invention disclosed herein possess severalimportant features in common. Among these are the slidable mounting of amovable jaw at the lower end of a tong arm together with power actuatedmeans for shifting the jaw toward and away from a xed jaw withoutaffecting the position of the tong arm or shifting its fulcrum point;the use of such power means for driving the movable jaw against the coilwall to preliminary compress the coil laminations and the subsequentavailability of a true tong action for tightening the grip on the thuscompressed coil wall for coil-lifting purposes; the availability of apowerful tong gripping action to preclude the dropping of the coil evenin the event of a power failure; the availability of such power meansfor shifting the movable jaw during transportation of the empty,load-free coil grab in accordance with an estimate of the wallvthicknessof the next coil to be engaged; the availability of the tong actionuntil such time as the coil wall has been fully straddled by the jaws;and the automatic disabling of the tong action prior to complete coilrelease so that it is not necessary to effect a full tong stroke toattain such tong disabling.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawings or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit of the invention. Only insofar as theinvention has particularly been pointed out in the accompanying claimsis the same to be limited.

Having thus described the invention what we claim as new and desire tosecure by Letters Patent is:

1. In a motorized coil grab of the character described for clamping thecylindrical wall of an involutely wound coil or the like and thereaftertransporting the coil from one location to another, in combination, aframe, a fixed jaw depending from said frame and designed for clampingengagement with the inner side of the cylindrical coil wall, a movablejaw depending from and slidably disposed on said frame, capable ofhorizontal movement forwardly toward and rearwardly away from said fixedjaw, and designed for clamping engagement with the outer side of thecylindrical coil wall, a tong arm pivoted medially of its ends to saidframe for swinging about a horizontal axis between two extreme positionsand in the general direction of the movements of the movable jaw, aprimary lift pin on the upper end of said tong arm and designed forengagement with an overhead hoist for exerting a lifting action on thetong arm, an elongated feed screw mounted for rotation on the frameabout an axis coincident with the path of movement of the movable jawand capable of limited axial sliding movement, means establishing athreaded connection between the feed screw and movable jaw wherebyrotation of the feed screw in opposite directions will effect horizontalmovement of the movable jaw in opposite directions respectively, meansdefining a rearwardly facing shoulder on the feed screw, means defininga forwardly facing shoulderon the lower end of the tong arm, theshoulder on the tong arm being designed for engagement with the shoulderon the feed screw when said lift pin is engaged and lifted by said hoistto force the feed screw to move in a forward direction, interengaginglimit stop means on the frame and tong arm for limiting the extent ofswinging movement of which the tong arm is capable when said lift pin isengaged and lifted by said lift hook, said interengaging limit stopmeans comprising a secondary lift pin on said tong arm adjacent to theupper end thereof, and an upwardly projecting framesupporting linkhaving a hook portion overlying said pin and designed for engagement bythe latter when the tong arm, during lifting thereof, has been swungthrough a predetermined angle in a direction to effect forward movementof the feed screw, said primary lift pin and tong arm serving to supportthe frame when said limit stop means is ineffective, said primary liftpin, a portion of said tong arm, said secondary lift pin, and saidframesupporting link serving to support the frame when said limit stopmeans is effective, and a motor for selectively rotating said feed screwin opposite directions.

2. In a motorized coil grab of the character described for clamping thecylindrical wall of an involutely wound coil or the like and thereaftertransporting the coil from one location to another, in combination, aframe, a fixed jaw depending from said frame and designed for clampingengagement with the inner side of the cylindrical coil wall, a movablejaw depending from and slidably disposed on said frame, capable ofhorizontal movement forwardly toward and rearwardly away from said fixedjaw, and designed for clamping engagement with the outer side of thecylindrical coil wall, a tong arm pivoted medially of its ends to saidframe for swinging movement about a horizontal axis between two extremepositions and in the general direction of the movements of the movablejaw, a lift pin at the upper end of said tong arm and designed forengagement with an overhead hoist, an elongated feed screw mounted forrotation on the frame about an axis coincident with the path of movementof the movable jaw and capable of limited axial sliding movement, meansestablishing a threaded connected between the feed screw and movable jawwhereby rotation of the feed screw in opposite directions will effecthorizontal movement of the movable jaw in opposite directionsrespectively, means defining a rearwardly facing shoulder on the feedscrew, means defining a forwardly facing shoulder on the lower end ofthe tong arm, the shoulder on the tong arm being designed for engagementwith the shoulder on the feed screw when said lift pin is engaged andlifted by said lift hook to force the feed screw to move in a forwarddirection, interengaging limit stop means on the frame and tong arm forlimiting the extent of swinging movement of which the tong arm iscapable when said lift pin is engaged and lifted by said hoist,releasable latch means for disabling said limit stop means, means forrendering said latch means effective when said tong arm is swungthroughout a predetermined minimum angle in a direction to effectrearward movement of the lower end thereof, and means for selectivelyrotating said feed screw in opposite directions.

3. in a motorized coil grab of the character described for clamping thecylindrical wall of an involutely wound coil or the like and thereaftertransporting the coil from one location to another, in combination, aframe, a fixed jaw depending from said frame and designed for clampingmovement with the inner side of the cylindrical coil wall, a movable jawdepending from and slidably disposed on said frame, capable ofhorizontal movement forwardly toward and rearwardly away from said fixedjaw, and designed for clamping engagement with the outer side of thecylindrical coil wall, a tong arm pivoted medially of its ends to saidframe for swinging movement about a horizontal axis between two extremepositions and in the general direction of the movements of the movablejaw, a lift pin at the upper end of said tong arm and designed forengagement with an overhead hoist, an elongated feed screw mounted forrotation on the frame about an` axis coincident with the path ofmovement of the movable jaw and capable of limited axial slidingmovement, means establishing a threaded connection between the feedscrew and movable jaw whereby rotation of the feed screw in oppositedirections will effect horizontal movement of the movable jaw inopposite directions respectively, means dening a rearwardly facingshoulder on the feed screw, means defining a forwardly facing shoulderon the lower end of the tong arm, the shoulder on the tong arm beingdesigned for engagement with the shoulder on the feed screw when saidlift pin is engaged and lifted by said hoist to force the feed screw tomove in a forward direction, a reversible electric motor operativelyconnected to said feed screw in driving relationship, interengaginglimit stop means on the frame and tong arm for limiting the extent ofswinging movement of which the tong arm is capable when the lift pin isengaged and lifted by said hoist, said interengaging limit stop meanscomprising a secondary lift pin on said tong arm and adjacent to theupper end thereof, and an upwardly projecting frame-supporting linkhaving a hook portion overlying said pin and designed for engagement bythe latter when the tong arm, during lifting thereof, has been swungthrough a predetermined angle in a direction to effect forward movementof the feed screw, said primary lift pin and tong arm serving to supportthe frame when said limit stop means is ineffective, said primary liftpin, a portion of the tong arm, said secondary lift pin, and saidframe-supporting link serving to support the frame when said limit stopmeans is effective, an electric circuit for the motor, a pair ofnormally closed limit switches disposed in said circuit and mounted onsaid frame in spaced relationship, and an actuating finger on the tongarm and movable into engagement with said limit switches to open thesame when said tong arm moves to its extreme positions respectively.

4. In a motorized coil grab of the character described for clamping thecylindrical wall of an involutely wound coil or the like and thereaftertransporting the coil from one location to another, in combination, aframe, a fixed jaw depending from said frame and designed for clampingengagement with the inner side of the cylindrical coil wall, a movablejaw depending from and slidably disposed on said frame, capable ofhorizontal move- 13 ment forwardly toward and rearwardly away from saidfixed jaw, and designed for clamping engagement with the outer side ofthe cylindrical coil wall, a tong arm pivoted medially of its ends tosaid frame for swinging movement about a horizontal axis between twoeXtreme positions and in the general direction of the movements of themovable jaw, a lift pin at the upper end of said tong arm and designedfor engagement with an overhead hoist, an elongated feed screw mountedfor rotation on the frame about an axis coincident with the path ofmovement of the movable jaw and capable of limited axial slidingmovement, means establishing a threaded connection between the feedscrew and movable jaw whereby rotation of the feed screw in oppositedirections will effect horizontal movement of the movable jaw inopposite directions respectively, means defining a rearwardly facingshoulder on the feed screw, means dening a forwardly facing shoulder onthe lower end of the tong arm, the shoulder on the tong arm beingdesigned for engagement with the shoulder on the feed screw when saidlift pin is engaged and lifted by said hoist to force the feed screw tomove in a forward direction, a suspension pin on said frame, a hookplate pivoted to the tong arm adjacent the upper end of the latter, saidhook plate being formed with a hook portion adapted to engage saidsuspension pin for lifting purposes, a latch pin on said hook plate, alatch member pivoted to the tong arm and having a latch seat adapted toreceive the latch pin therein, carn means on said 'nook plate andsuspension pin for guiding the latch pin into operative register withthe latch seat when said tong arm is swung throughout a predeterminedminimum angle in a direction to effect rearward movement of the lowerend thereof, an electric motor for selectively rotating said feed screwin opposite directions, a circuit for said motor, and meansautomatically operable during movement of the tong arm between said twoextreme positions for preventing energization of the motor circuit.

5. In a motorized coil grab, the combination set forth in claim 4 andwherein said means for preventing energization of the motor circuitcomprises a limit switch mounted on said frame, and an actuating lingeron said hook plate, said actuating finger being operable to actuate thelimit switch when the tong arm is in either of its extreme positions,said limit switch being operable when actuated to render the motorcircuit effective.

References Cited in the le of this patent UNITED STATES PATENTS2,718,321 Westermeyer Sept. 20, 1955 2,945,609 Benes et al. July 19,1960 3,076,674 Anderson Feb. 5, 1963

1. IN A MOTORIZED COIL GRAB OF THE CHARACTER DESCRIBED FOR CLAMPING THECYLINDRICAL WALL OF AN INVOLUTELY WOUND COIL OR THE LIKE AND THEREAFTERTRANSPORTING THE COIL FROM ONE LOCATION TO ANOTHER, IN COMBINATION, AFRAME, A FIXED JAW DEPENDING FROM SAID FRAME AND DESIGNED FOR CLAMPINGENGAGEMENT WITH THE INNER SIDE OF THE CYLINDRICAL COIL WALL, A MOVABLEJAW DEPENDING FROM AND SLIDABLY DISPOSED ON SAID FRAME, CAPABLE OFHORIZONTAL MOVEMENT FORWARDLY TOWARD AND REARWARDLY AWAY FROM SAID FIXEDJAW, AND DESIGNED FOR CLAMPING ENGAGEMENT WITH THE OUTER SIDE OF THECYLINDRICAL COIL WALL, A TONG ARM PIVOTED MEDIALLY OF ITS ENDS TO SAIDFRAME FOR SWINGING ABOUT A HORIZONTAL AXIS BETWEEN TWO EXTREME POSITIONSAND IN THE GENERAL DIRECTION OF THE MOVEMENTS OF THE MOVABLE JAW, APRIMARY LIFT PIN ON THE UPPER END OF SAID TONG ARM AND DESIGNED FORENGAGEMENT WITH AN OVERHEAD HOIST FOR EXERTING A LIFTING ACTION ON THETONG ARM, AN ELONGATED FEED SCREW MOUNTED FOR ROTATION ON THE FRAMEABOUT AN AXIS COINCIDENT WITH THE PATH OF MOVEMENT OF THE MOVABLE JAWAND CAPABLE OF LIMITED AXIAL SLIDING MOVEMENT, MEANS ESTABLISHING ATHREADED CONNECTION BETWEEN THE FEED SCREW AND MOVABLE JAW WHEREBYROTATION OF THE FEED SCREW IN OPPOSITE DIRECTIONS WILL EFFECT HORIZONTALMOVEMENT OF THE MOVABLE JAW IN OPPOSITE DIRECTIONS RESPECTIVELY, MEANSDEFINING A REARWARDLY FACING SHOULDER ON THE FEED SCREW, MEANS DEFININGA FORWARDLY FACING SHOULDER ON THE LOWER END OF THE TONG ARM, THESHOULDER ON THE TONG ARM BEING DESIGNED FOR ENGAGEMENT WITH THE SHOULDERON THE FEED SCREW WHEN SAID LIFT PIN IS ENGAGED AND LIFTED BY SAID HOISTTO FORCE THE FEED SCREW TO MOVE IN A FORWARD DIRECTION, INTERENGAGINGLIMIT STOP MEANS ON THE FRAME AND TONG ARM FOR LIMITING THE EXTENT OFSWINGING MOVEMENT OF WHICH THE TONG ARM IS CAPABLE WHEN SAID LIFT PIN ISENGAGED AND LIFTED BY SAID LIFT HOOK, SAID INTERENGAGING LIMIT STOPMEANS COMPRISING A SECONDARY LIFT PIN ON SAID TONG ARM ADJACENT TO THEUPPER END THEREOF, AND AN UPWARDLY PROJECTING FRAMESUPPORTING LINKHAVING A HOOK PORTION OVERLYING SAID PIN AND DESIGNED FOR ENGAGEMENT BYTHE LATTER WHEN THE TONG ARM, DURING LIFTING THEREOF, HAS BEEN SWUNGTHROUGH A PREDETERMINED ANGLE IN A DIRECTION TO EFFECT FORWARD MOVEMENTOF THE FEED SCREW, SAID PRIMARY LIFT PIN AND TONG ARM SERVING TO SUPPORTTHE FRAME WHEN SAID LIMIT STOP MEANS IS INEFFECTIVE, SAID PRIMARY LIFTPIN, A PORTION OF SAID TONG ARM, SAID SECONDARY LIFT PIN, AND SAIDFRAMESUPPORTING LINK SERVING TO SUPPORT THE FRAME WHEN SAID LIMIT STOPMEANS IS EFFECTIVE, AND A MOTOR FOR SELECTIVELY ROTATING SAID FEED SCREWIN OPPOSITE DIRECTIONS.